Claritifcation about the `max_position_embeddings` argument

Referring to this Colab Notebook:

While initializing the RobertaConfig:

config = RobertaConfig(
    vocab_size=52_000,
    max_position_embeddings=514,
    num_attention_heads=12,
    num_hidden_layers=6,
    type_vocab_size=1,
)

Why do we set max_position_embeddings to 514 when the maximum sequence length is set to 512 in the notebook?